Carpenters, mason workers, construction workers as well as home do-it-yourselfers require the ability to align objects either parallel or perpendicular to the direction of the Earth""s gravitational pull. In recent years, a number of tools have been developed to project lines on walls and other vertical surfaces using lasers and laser diodes.
A variety of leveling tools have employed lasers to aid in placing a line on a wall or other vertical surface. Some leveling tools require a user to manually adjust the laser""s orientation using one or more spirit levels as references. These tools emit a light beam defining line along a wall that may fall at any angle with respect to the wall but are only as accurate as the user""s eye can provide.
To improve accuracy, other leveling tools use a laser diode mounted on a pendulum to automatically level the laser""s emitted beam. Many pendulum levels use a knife""s edge as a pivot axis or use a pin as a pivot point. Unfortunately, sharp knife edges and pin points are fragile and are easily damaged as a result of sharp impact forces.
Some tools employ pendulums to emit two beams of light: one horizontally to the left and another horizontally to the right. To emit a beam vertically upwards, still other leveling tools place a laser on a float suspended in a liquid. Each of these tools emit beams of light that are fixed in either a vertically plumb direction (up or down) or in a horizontal direction (left or right).
Known tools that emit self-leveling beams in more than one direction (up, down, left, right) require multiple lasers or multiple lenses and mirrors. For example, a tool that emits a plumb line up and horizontally to the right might use two separate lasers, one for each orientation. A tool that emits a plumb line both up and down, in addition to horizontally left and right might use four lasers. The addition of lasers and optics substantially increases the overall complexity and cost of the tool.
One factor, in determining the visible length that a tool will project light along a wall, is the perpendicular distance between the wall and the light source. The higher away from the wall that the beam originates, the farther the beam will be visible along the wall. Some known tools have a deep profile that is fixed allowing the tool to emit a beam significantly farther than other tools with lower profiles. One drawback to a deep profile tool is that it is physically larger than lower profile tools.
Therefore, there exists a need for an inexpensive and sturdy line generator that emits, on a vertical surface, a self-leveling vertical plumb line (light beam) either up or down, or a level horizontal line either left or right. Further, there exists a need for a tool that has the size advantage of being a low profile tool and the advantage of stand-off distance of a high profile tool.
In some embodiments, a light emitting tool comprising a housing; a pendulum having a light source; and a plurality of receiving elements defined in one of the housing and the pendulum, and a plurality of extensions defined on the other of the housing and the pendulum; wherein the plurality of extensions define a plurality of pivot axes of the pendulum and the pendulum is substantially free in the housing; and wherein the receiving elements cooperatively interact with the plurality of extensions thereby to bound free movement of the pendulum.
In some embodiments, method to project a light beam to a surface in any one of four directions using a light emitting tool, the method comprising the acts of directing the tool towards the surface; rotating the tool to an orientation near that of the desired direction; and allowing the tool to self-balance, thereby projecting the light beam from the tool and towards the surface in the desired direction.